Dodge Grand Caravan 1999 - 3.8L low compression on one cylinder

[MaximumMini]

Yeah pics are pics. Sure looks like a chunk out of that land between oil ring and 2nd compression ring just above the boss area for the wrist pin.
Optical illusion ?

Yes. Nothing missing. It stayed in one piece.

 

[meep]

@MaximumMini - are you going to remove the rings? A good cleaning would probably benefit from slipping the rings out and making sure you can clean out the channels. And at this point, I’m thinking new rings get installed instead of the old?

I had 3 Volvo S60s, the first gen, all purchased at over 100k miles. One of them consumed a quart of oil roughly every 900 miles. I started running half a can of seafoam in it with a ~7,000 mile interval. After 20k miles of this, the oil consumption basically stopped. It might have used half a quart over 7,000 miles after that. I’d refresh the seafoam around 5,000 miles, or 2k before the OC. I don’t really know what it did or where it did it, but I suspect it cleared up the ring landings.

 

[Fordiesel69]

I was going to suggest either a very early piston skirt break, or a ring land break. Chrysler 4.7 / 3.7, and somethimes the 3.8 / 3.3L do this. If you catch a piston skirt break early the cylinder will look good. After 5 ~ 15k miles you will see bore polishing and or vertical gouges on the cylinder surface. The good news is with a ring land breakage a quick run of the ball or flat stone hone will fix it right up.

 

[Lockasiam]

Well guys, I THINK I finally found the problem.

Let me show you a few pictures. Tell me if this is it or not
No broken or stuck rings.....but broken RING LANDS between the rings. <scratches my head>
so will this cause catastrophic compression loss ? ;-)

What likely caused this?
No evidence of any damage to any heads, pistons or valves from detonation.
View attachment 274020

i need a big obnoxious red circle and an arrow to see what you guys are, looks like a normal piston

 

[Lockasiam]

nevermind i see it

​

 

[MaximumMini]

i need a big obnoxious red circle and an arrow to see what you guys are, looks like a normal piston

I actually thought about adding those before I posted that.....
Then I thought...geezz, someones gonna rant about the annoying red circle and arrows obscuring the view

 

[Lockasiam]

Is this engine gonna get piston(s) and rings? I think a new piston off rock auto plus a 6 set of rings is about $100 before shipping, not including all the gaskets you now have to do

 

[MaximumMini]

Is this engine gonna get piston(s) and rings? I think a new piston off rock auto plus a 6 set of rings is about $100 before shipping, not including all the gaskets you now have to do

Well, the only cylinder with low compression was No 2. The rest are fine. I also noticed today for the first time that that one cylinder had a new fuel injector installed. The bearings look great and it has 160k miles on the clock. 300k+ on a well maintained 3.8L is common.
So, I'm going to check the bore dimensions on all three that have the head off and if within specs, I'll just hone and re-ring this one cylinder and put it back together. Getting to this point is really only about an hours work so if I need to take the motor out later no biggie.

Like your avatar

 

[Lockasiam]

sounds good, my 3.8 (2005) has 243k on it and no sign of stopping

Like your avatar

Thanks, it's my cat that died last year at the ripe age of 17 years old

 

[Marcozi]

The things you need to check on that piston are the oil drain holes. They may

Well, the only cylinder with low compression was No 2. The rest are fine. I also noticed today for the first time that that one cylinder had a new fuel injector installed. The bearings look great and it has 160k miles on the clock. 300k+ on a well maintained 3.8L is common.
So, I'm going to check the bore dimensions on all three that have the head off and if within specs, I'll just hone and re-ring this one cylinder and put it back together. Getting to this point is really only about an hours work so if I need to take the motor out later no biggie.

Like your avatar

Make sure the oil drain holes are clean.

 

[MaximumMini]

sounds good, my 3.8 (2005) has 243k on it and no sign of stopping


Thanks, it's my cat that died last year at the ripe age of 17 years old

I know the pain.
He looks like he was a good fella.
What was his name?

 

[Lockasiam]

What was his name?

Riley, he may have been 17 but when he died he still acted like he was maybe 1

 

[D60]

I hate minivans and the 3.8, but I've really enjoyed this thread. I never knew ring land failure like this was a thing! Very cool!

I commend the OP for just rolling up his sleeves and digging in. He's done great work (as if my assessment matters)

I've now also learned my one thing for the day so I can take a nap.....

 

[Lockasiam]

I hate minivans and the 3.8

 

[BornSlippy]

I had a 2003 Grand Caravan 3.8. Really liked that van.

 

[Lockasiam]

I had a 2003 Grand Caravan 3.8. Really liked that van.

I enjoy my 05 but I’m sure it doesn’t appreciate being used like a truck sometimes

 

[D60]

It's OK! Some guy's opinion on the internet is worth less than your morning constitution after 2 cups of coffee and a big bran muffin. Take a breath, you'll be fine.

 

[Oliveoil2]

Well, the only cylinder with low compression was No 2. The rest are fine. I also noticed today for the first time that that one cylinder had a new fuel injector installed. The bearings look great and it has 160k miles on the clock. 300k+ on a well maintained 3.8L is common.
So, I'm going to check the bore dimensions on all three that have the head off and if within specs, I'll just hone and re-ring this one cylinder and put it back together. Getting to this point is really only about an hours work so if I need to take the motor out later no biggie.

Like your avatar

This is exactly what you should do! I was reading the entire post and was wondering when someone would purpose this. Please let us know how it goes.

 

[MaximumMini]

Different strokes for different folks.
I've had chevy's, fords, pontiacs, volkswagens, audis, mercedes, Nissans, Toyotas and a few I forget.

of all of them I love the caravans the most. Mostly the Grand Caravans especially.
with the seats out I have 12ft of rain proof cargo space.
Put them in I can carry the whole team.

I guess I'd make a great soccer mom

This is exactly what you should do! I was reading the entire post and was wondering when someone would purpose this. Please let us know how it goes.

Thank you OliveOil2

 

[kschachn]

Thanks.
Tomorrow I'll get dimensions to see if the cylinder is out of round.
I have inside mics for that.

How is it coming on that measurement?